Applicants claim priority under 35 U.S.C. xc2xa7119 of German Application No. 199 52 168.9 filed Oct. 29, 1999. Applicants also claim priority under 35 U.S.C. xc2xa7120 of PCT/EP00/08106 filed Aug. 19, 2000. The international application under PCT article 21(2) was not published in English.
The invention relates to a drive for escalators or moving sidewalks that is mounted within the step or pallet belt and comprises a distributor gear with two output shafts, specifically one for the handrail and one for the step or tread belt, whereby each output shaft is provided with a drive gear for driving the shaft associated with it, as well as a drive unit that is mounted between the drive shafts for the distributor gear. The drive unit comprises at least one electric motor with a planetary gear.
Such a drive is known from DE 35 26 905 C2 of the applicant firm of the present application. Said known drive comprises a distributor gear with two output shafts on which a motor drive module is arranged. Via a multi-stage planetary gear, said module drives a toothed gear that is installed in a fixed manner in the distributor gear. Said toothed gear is actively connected with the toothed gears of the output shafts for the step belt and the handrail. The toothed drive gear is supported in the housing of the distributor gear, whereas the motor drive module is forming a separate unit and is actively connected with the toothed drive gear after the assembly work has been completed.
Based on the given dimensions with which the output shafts ate spaced in conjunction with escalators or moving sidewalks, and given the fact that the motor drive module is mounted between the output shafts, the transmission ratio achieved with such a design of the construction of the drive with the toothed gears, which are arranged fixed in the distributor gear, is only relatively low. The distributor gear itself thus contributes only little to achieving the required transmission ratio, so that a motor drive module is required that needs expenditure accordingly, in which the required translation or reduction ratio is made available to a large extent by the planetary gear. Furthermore, both the assembly of the distributor gear and the installation of the motor drive unit on the housing of the distributor gear require a relatively great amount of expenditure.
The problem of the invention is to improve a drive of the type specified above in such a way that in particular its assembly is simplified and components can be used that are simpler with respect to their construction and therefore less costly.
Said problem is solved according to the invention in connection with a drive of the type specified above in that the electric motor, the planetary gear, and a drive step linked with the power take-off of the planetary drive for directly driving at least the drive wheel of the output shaft for the step or pallet belt, are combined in one single assembly unit that can be secured on the distributor gear.
As opposed to the prior art as represented by DE 35 26 905 C2, thus the central drive for the distributor gear is no longer mounted in the distributor gear itself, but realized in the form of a drive step that is connected with the planetary gear, and forming one single assembly unit combining the electric motor and the planetary drive. Such a drive step may be designed in this connection as a reduction gear, so that reduction can be saved in the planetary gear itself, which reduces the expenditure required for the planetary gear. Furthermore, the assembly of the distributor gear itself is substantially simpler because it does not contain the actual driving elements. Moreover, the single assembly unit can be installed in a simpler manner because it needs to be flanged only to the housing of the distributor gear, or secured in some other way.
According to a first embodiment of the invention, provision is made that the driving gears of both output shafts each are designed in the form of a toothed gear, and that the drive step of the assembly unit drives both toothed gears.
As an alternative, it is possible also to make provision that the drive step is designed only for directly driving the drive wheelxe2x80x94the latter being realized in the form of a toothed gearxe2x80x94of the output shaft for the step or pallet belt; and that the output shaft for the handrail is connected with the output shaft for the step or pallet belt via a drive chain.
It is particularly preferred if provision is made that the drive step of the assembly unit is designed in the form of a geared step that comprises a pinion linked with the power output of the planetary gear, and at least one intermediate gear. In this way, it is possible in a simple way to accommodate an additional reduction outside of the planetary gear, but in the single assembly unit that is connected in a fixed manner with the planetary gear, so that step-down gearing in the planetary gear itself can be saved.
If both output shafts are equipped with toothed driving wheels, provision is naturally made in that case that the gear step comprises two intermediate gears that may be advantageously provided with different width dimensions.
For the purpose of providing the bearing of the one or more intermediate gears in the assembly unit in the simplest possible way, provision is advantageously made that at least one of the intermediate gears is supported on a journal pin that is connected with the housing of the assembly unit in a fixed manner.
Furthermore, in a manner that is known per se, provision can be advantageously made that two or more assembly units are arranged on the distributor gear in parallel with the output shafts. Such an embodiment, viewed by itself, is known from DE 35 26 905 C2, to which reference is made in this regard.